The clinical profile of systemic sclerosis without a 'scleroderma pattern' at nailfold capillaroscopy: results from the multicenter SPRING registry of the Italian Society of Rheumatology.

Background: Microvascular alterations can be detected with nailfold videocapillaroscopy, useful for systemic sclerosis (SSc) diagnosis upon identification of the "scleroderma pattern" (NVC-SP). However, this pattern is missing in a subset of SSc patients. Methods: This retrospective analysis on the multicenter Italian SPRING cohort of SSc patients assessed the prevalence and characteristics of patients without NVC-SP. Associations with demographic and clinical features were evaluated using logistic regression (cross-sectional) and mixed-effects models (longitudinal). Results: Out of 1689 SSc patients with available NVC information, 90 (5.3%) did not have the NVC-SP. These patients were older at SSc onset (53 vs. 49 years) and more frequently sine scleroderma (31% vs 12%, p < 0.001). The overall burden of vascular complications was milder in this subset, with a lower prevalence of pitting scars (33% vs 48%), telangiectasias (52% vs 74%), and calcinosis (3.4% vs 12%). During the follow-up, mRSS remained lower (60-month mean 4 vs 7, p = 0.002), as well as the estimated probability of vascular complications. Moreover, despite comparable values at baseline, DLCO remained significantly higher in patients without NVC-SP at the following time points (12, 24, and 60 months, p < 0.05). The presence of "late" NVC-SP was independently associated with ILD (OR 1.83, 95% CI 1.05-3.18). Conclusions: The absence of NVC-SP in 5.3% of SPRING SSc patients may identify a subset characterized by milder disease, with a lower burden of vascular and organ complications. Conversely, lung involvement was more frequently observed in patients with more severe NVC microangiopathy.